So you're you're ignoring all the evidence and dismissing the "multiple shooter theory" based on a terminally ill Giancana mob associate's not dying as fast as predicted?Jack Ruby was convicted of Oswald's murder and died four years later in prison of a pulmonary embolism, in addition to cancer and other health complications. If you entertain the "multiple shooter" theory, then what did Jack Ruby have to gain by killing Oswald?
There is more hard evidence proving a "multiple shooter theory" than there is a single shooter theory, unless you're basing your argument on a corrupt Warren Commission Report.
Investigators approached Ruby later when he was in jail to question him in his involvement and he said 'Get me out of here (into a safe place) and we'll talk'. They didn't and he didn't.